Study On Preparation Of Galacto-Mannan-Oligosaccharides By Microwave-Enzyme Hydrolysis Of G. Heterophylla Gum In Technology

Galacto-mannan-oligosaccharides(GMOS) is incomplete degradation product of galactomannan.It has many kinds of characteristics as can obviously promote beneficial fungus multiplication that take Bifidobacterrium bacillus as representative in the human body's intestinal tract,also has the function that reduced disease germ from animal intestinal tract,and enhances immunity,intestines mucous membrane and so on.This article uses the microwave-enzyme hydrolysis to degrade the G heterophylla gum to prepare galacto-mannan-oligosaccharides,and has carried on the separation and extraction in the industrialization angle.The main research content is as follows:Through the microwave function coupling withβ-mannanase degrades the G. heterophylla gum to reduce the viscosity in this sistem,the research prepares galacto-mannan-oligosaccharides in the technological conditions as well as studies on the oligosaccharides composition in the hydrolysate and the industrialization production.Through 1,4,6,8 and 24 hours hydrolysis,separately obtains five kinds of G. heterophylla gum hydrolysate.Their reducive ability by D-mannose gauge is in turn——6.02%,13.05%,15.61%,17.55%,19.42%,the G.heterophylla gum has had the remarkable degeneration,produces many reducible terminal.Studies the hydrolysis advancement through determination every half an hour with kinematic viscosity,which discovered carring on rapidly in the initial hour responded.In 5min,the kinematic viscosity (hydrolisis G heterophylla gum) has dropped from 2250cps to 165cps(dropped 92.6%). After 1h,drops to 74cps,after 12h falls to 6cps.The reaction time and the temperature are big influences to the enzymolysis process, but pH's is relative small.Had determined through the orthogonal experiment the enzyme hydrolysis is the best craft to prepares galacto mannan-oligosaccharides,namely the substrate concentration is 2.0%,adds the enzyme in 20U/g,the hydrolysis temperature is 65℃,reacting system pH is 7.0,hydrolysis time is 8h.The hydrolysis of polymerization in average degree is the 5.6.By TLC examination,the hydrolysate mainly is oligosaccharides above two sugars.Use the microwave and the strong oxidant,which coupled the KOH to carry the pretreatment on G.heterophylla gum to cause its viscosity to drop,the molecular chain preliminary break.This innovation pretreatment method may enhance the substrate concentration of emzymolysis greatly,realizes the industrialization of galacto-mannan-oligosaccharides. Has determined the microwave pretreatment optimizati- on plan through the orthogonal experiment,namely KOH recruitment for G.heterophylla gum multi-syrups is 1.5%;The H₂O₂ recruitment for the multi-syrups is 20%,and water is 15%.To 20g gum powder,the suitable microwave power is 320W,the microwave response time is 3min. Useing this in the enzymolysis after microwave,the density of processing from original 2% enhancing to 10%above.The molecular weight of G.heterophylla gum by using the microwave pretreatment, and the galacto-mannan-oligosaccharides content and molecular weight distributions of the hydrolysates were estimated using capillary viscometry and high performance gel filtration chromatography(HPLC).The result indicated that after the processing,the substrate the relative molecular weight degrade to 20903Dr from initial 206000 Dr,when the hydrolysis to 24h,it drops to 1040Da.The average degree of polymerization is 5.6. Galacto-mannan-oligosaccharides comparative content is 73.8%,the monosaccharide accounts for 26.23%,its low polyose content enhanced 4.3%compared to the direct product of enzymolysis.Through with the comparison of ethyl alcohol extraction and the activated charcoal column chromatographic analysis,had determined by ultra filters the technology which the coupling nano-filtration to realize the industrialization production.After processing,it causes to compare the macro-molecule of oligosacch- arides to filter out,simultaneously lowers of the molecular oligosaccharides to obtain concentrates,and the desalinization rate achieves 95.6%,the purity of Galacto-mannan-oligosaccharides achieves 95.5%.It achieves the goals of the separation,the purification,the desalinization and the concentration.It raises effectively mellowly has not only enhanced the purity of oligosaccharides,moreover the inorganic salt is unable to remove,still needed to desalt through other equipment.The activated charcoal column is prominent to the separation effect of oligosaccharides,finally indicated that it separates Galacto-mannan-oligosaccharides to 2～3 sugar components,uses HPLC then to be possible again to make the sole component,provides the sterling for the structure and the functional analysis of oligosaccharides.